Antifungal Effect of Essential Oils from Five Kinds of Rutaceae Plants – Avoiding Pesticide Residue and Resistance

Panax notoginseng root is a traditional Chinese herb, of which the yield and quality have been seriously affected by microorganisms, and is commonly used to treat various kinds of bleeding. In this experiment, the effects of the antifungal properties of essential oils (EOs) from five kinds of Rutaceae plants on the growth of three kinds of pathogens were studied to develop natural, environmentally friendly antifungal agents. Citrus medica EO was found to have stronger inhibitory effects on the growth of pathogenic fungi in vitro than other EOs with the Oxford cup method, of which the chemical composition was further investigated by GC/MS. The major components were d‐limonene (22.79 %) and γ‐terpinene (9.71 %). The antifungal activities were evaluated by MIC and FIC assays. In these assays, C. medica EO, d‐limonene and γ‐terpinene were effective against three pathogens of P. notoginseng with MIC values ranging from 0.12 to 12.05 mg/mL. The association between hymexazol and C. medica EO showed a high synergistic effect with lower FIC index values (FICi=0.31–2.00). Furthermore, C. medica EO was further assessed in P. notoginseng planted in a continuous cropping soil (CCS) and was found to reduce the disease incidence and disease severity compared with P. notoginseng planted in CCS only without EO addition. This finding suggested that C. medica EO has potential as a natural environmentally antifungal agent against pathogens of P. notoginseng, ensuring its safety.